The present invention relates to a plasma processing method for plasma-etching magnetic film (or magnetic layer) material.
In magnetic storage devices, high recording density is increased every year and reproducing heads are also required to cope with high recording density. In order to meet the requirements, Current-in-Plane-Giant Magneto-Resistance (CIP-GMR) sensors in which current is sent in a film (or layer) surface of a magnetoresistance effect film (or layer) including a thin nonmagnetic layer disposed between two kinds of ferromagnetic layers have been developed and are applied as the reproducing heads.
At present, the reproducing heads are being shifted to Tunneling Magneto-Resistive (TMR and hereinafter referred to as TMR) heads and Current Perpendicular to the Plane-Giant Magneto-resistance (CPP-GMR) heads used by sending current in a layer thickness direction of a lamination layer. In order to increase the reproduced output, it is general to enhance the MR (Magneto-Resistive) ratio and at present TMR heads having the highest MR ratio are widely adopted.
Further, in the manufacturing process of the TMR heads, an etching process and a layer formation process of magnetic material used as material of TMR elements are also one important research and development and various processes and plasma processing devices are subjected to research and development.
Under the present circumstances, the etching process and the layer formation process of magnetic material in the manufacturing process of devices such as TMR elements employ separate plasma processing devices as shown in FIG. 1. Further, when a sample is conveyed to a layer formation processing device after the etching processing, there arises a problem that the devices are deteriorated due to contaminants or useless contaminating matters attached to the surface of the sample. Accordingly, in order to prevent the deterioration of devices due to the contaminants or useless contaminating matters, cleaning processing is performed to the devices after the etching processing and thereafter the layer formation processing device is used to perform layer formation processing.
For example, JP-A-8-335571 discloses cleaning processing measures using an etching treatment apparatus in which etching means 10, ashing means 20, rinsing means 30 and drying means 40 are disposed within the apparatus of one unit and specimens taken out one by one from a cassette are sequentially treated by using each means and which includes control means for storing the treated specimens in the cassette, although it is necessary to spend enormous investment in plant and equipment and enormous manufacturing time in the device manufacturing process. Accordingly, it is necessary to perform the etching processing and the layer formation processing in the same apparatus or the same vacuum chamber.
For example, as a semiconductor manufacturing device capable of performing a plurality of treatments by a single device in a thin film (or layer) formation process and capable of manufacturing semiconductor elements with high quality, JP-A-2003-243362 discloses a semiconductor manufacturing device which includes a vacuum container, an insulation dielectric disposed in the vacuum container and having an electrode plate disposed on one surface and a wafer disposed on the other surface, voltage application means for applying voltage between the electrode plate and the wafer and heating means for heating the wafer and in which the voltage application means applies the voltage to thereby generate electrostatic suction force between the electrode plate and the wafer so that the wafer is sucked to be held on the surface of the insulation dielectric and the wafer is subjected to processing for manufacturing of the semiconductor elements, the semiconductor manufacturing device being characterized in that the insulation dielectric has a value of volume resistivity ρ falling within the range of 108Ω cm<ρ<1013Ω cm in a heating temperature range for forming thin film (or layer). However, since the plasma processing device as disclosed in JP-A-2003-243362 is supposed as the plasma processing device which performs two treatments of the etching processing and the layer formation processing, it is difficult to apply measures disclosed in JP-A-9-45756 as it is.
Further, JP-A-2003-243362 discloses an etching method for suppressing adhesion of a reaction product to an inner wall of a vacuum container and a cleaning method for efficiently removing the adhered reaction product in a plasma processing device for processing nonvolatile material by using a Faraday shield.